Jupiter Dolichenus was a Roman god whose mystery cult was widespread in the Roman Empire from the early-2nd to mid-3rd centuries AD. Like several other figures of the mystery cults, Jupiter Dolichenus was one of the so-called 'oriental' gods, that is, Roman re-inventions of ostensibly foreign figures in order to give their cults legitimacy and to distinguish them from the cults of the traditional Roman gods.
Like the other mystery cults (including the other pseudo-oriental ones), the cult of Jupiter Dolichenus gained popularity in the Roman Empire as a complement of the open 'public' religion of mainstream Roman society. Unlike the Roman public cults, but like the other mysteries, the temples of the cult of Jupiter Dolichenus were nominally closed to outsiders and followers had to undergo rites of initiation before they could be accepted as devotees. As a result, very little is known about the cult's beliefs and practices from the few clues that can be obtained from the sparse iconographic, archaeological or epigraphic evidence.
The cult gained popularity in the 2nd century AD, reached a peak under the Severan dynasty in the early 3rd century AD, and died out shortly thereafter. At least nineteen temples (including two discovered in 2000) are known to have been built in Rome and the provinces which, while substantial, is far below the popularity enjoyed by the comparable pseudo-oriental cults of Mithras, Isis or Cybele.
Until the late 20th-century, Roman exoticism was usually taken at face value, and Jupiter Dolichenus was therefore – like the other pseudo-oriental figures also – assumed to have really been a Roman continuation of an oriental figure. In the case of Jupiter Dolichenus, the exoticism was attributed to a interpretatio romana derivation from a semitic Hadad-Baal-Teshub cult, which had its cult center on a hill (37°07′40″N 37°20′43″E / 37.12778°N 37.34528°E) near Doliche, 30 Roman Miles west of Samosata on the Euphrates, in the Commagene in eastern Asia Minor (The present-day name of the hill is Baba Tepesi, "Father Teshub". Historical Doliche is on a height now known as Keber Tepe, just west of Dülük, Gaziantep Province, Turkey). It is from the city of Doliche that the epithet 'Dolichenus' "of Doliche" was adopted. However, since the 1980s it has become increasingly evident that the exotic gloss the Romans gave to their so-called 'oriental' gods was mostly superficial, and based primarily on Roman perceptions (hearsay and their own imagination) of what the foreign gods were like. Accordingly, in the context of Roman religion, the term 'oriental' no longer carries much weight and is now mostly only used as an archaeological docket tag. (This development applies to all Roman 'oriental' gods equally; for a discussion of the issue in relation to Jupiter Dolichenus, see especially Bunnens 2004). The cult of Jupiter Dolichenus is especially difficult to assess in this respect because the archaeological finds at Dülük indicate that, at some point, Roman material was exported to Doliche, thus obscuring the distinction between Roman and native cult there. These scholastic issues notwithstanding, the Romans perceived Jupiter Dolichenus as 'Syrian', and that perception, not the reality, influenced the Roman world. Reinvented or not, the Roman cult appears to have been informed by Baal's roles as a national god and as a 'king' god (i.e. the senior-most of his pantheon), both aspects also being features of Roman Jupiter. How much doctrine (if any) the Romans borrowed remains unknown.